The present invention relates to an operation support system for a facility of supplying a plurality of energy forms such as electric power and heat, and more particularly to the system which properly supports the operation of the energy supply facility if change of demands cannot be precisely predicted.
As a typical example of an electric power or heat energy supply facility, there have been proposed a gas turbine (that supplies electric power and exhaust heat vapor by gas), a steam turbine (that supplies electric power by steam), a steam absorption refrigerator (that supplies chilled water by steam), an electric turbo refrigerator (that supplies chilled water by electric power), and so forth. The energy supply facility composed of those devices are difficult to be properly operated on account of the following two reasons. First, the energy supply facility is arranged to keep those devices closely related with one another in such a manner that the gas turbine and the steam turbine are complemented with each other in respect of the electric power supply and the steam absorption refrigerator collects exhaust heat from the steam turbine. Second, the energy demand may fluctuate depending on variables such as a weather and a temperature or any obscure cause.
In order to overcome these difficulties, the two background arts have been proposed. The first background art is a method of patterning an operation method (such as a start and stop time and a number of operating devices) and operating the facility according to the pattern. The concrete example of the target operation pattern is described in the page 6 of xe2x80x9c""99 Collection of Energy Saving Cases (first volume)xe2x80x9d edited by the Energy Saving Center (Incorporated Foundation), pages 786 to 787 of xe2x80x9c""99 Collection of Energy Saving Cases (second volume)xe2x80x9d edited by the Energy Saving Center (Incorporated Foundation), and page 53 of xe2x80x9cEnergy Saving Diagnosis and Concrete Measuresxe2x80x9d edited by NTS (Limited). By predetermining such an allowable target operation pattern as coping with some demand fluctuations, the operation enables to operate the energy supply facility with safety according to the predetermined operation pattern, which makes the safety supply of energy possible.
The second background art is described in JP-A-11-346438. The method of the background art is arranged so that for supplying an operator with a future predicted value of an electric power demand, the electric power demand is predicted at each interval as estimating a prediction error and are displayed. The application of this method makes it possible for an operation to know a prediction-deviating range or possibility and thereby to operate the energy supply facility according to the range or possibility. For example, if a future power demand may greatly exceed the prediction value, the application of this background art makes it possible for the operator to easily determine that one more generator than usual needs to be started. Or, if the future power demand may substantially match to the prediction value, the application of this background art makes it possible for the operator to easily determine that a reserve of energy may be partially reduced.
The first background art has concerned with the method of realizing the safety operation of the energy supply facility. This art may, however, burdens itself with the additional operation cost. For example, when both the electric power and the steam are supplied by the gas turbine, assuming that the predetermined target operation pattern of the gas turbine is at the xe2x80x9cconstant full operationxe2x80x9d and the gas turbine supplies more steam than needed according to the target operation pattern, the surplus stream is abandoned. It is certain that the energy may be supplied with safety according to this target operation pattern, but the surplus stream is abandoned. The operation cost thus may be increased more than needed.
The second background art provides a hint of keeping the electric power safety supply and the operation cost reduction in prompting an electric power system in compatibility by presenting the prediction value of the power demand with an error range to an operator. However, unlike the promotion of the electric power system, as to the electric power or heat energy supply facility built in a factory or a building, since a plurality of energy supply facilities are closely related with one another, even if the demand prediction values of electric power, steam, heated air and cool air may be presented to the operator together with their error ranges, the operator cannot easily determine how to cope with each prediction error with its error range. As one example, consider the energy supply facility composed of a combined cycle generator device and a heat recovery device, the combined cycle generator device serving to drive a steam turbine by using part of exhaust stream from the gas turbine and the heat recovery device serving to utilize the remaining exhaust stream for a water heater. Even if the gradual increase of the demand prediction values of both the electric power and the water heater load is quantitatively presented to the operator, the operator cannot easily determine how to cope with the demand prediction value.
The reason of the difficulty in determining how to cope with the prediction value is placed on a sophistication of an energy supply facility configuration and function in using many kinds of energies such as electric power, stream and chilled water. For example, as one of the methods of coping with the increase of the power demand, there may be proposed a method of raising a steam turbine output. This method may bring about an adverse effect by a shortage of a steam supply for a water heater because of increasing the steam consumption of the steam turbine. Even if the steam supply is not in short, at a certain unit price of the electricity tariff, the cost may be lowered not by raising the output of the steam turbine but by increasing the electricity bought from the commercial electric power. As indicated by this example, the operator cannot easily determine whether or not the manipulation of raising the steam turbine output is in proper from both viewpoints of safety supply and reduction of an operation cost.
It is an object of the present invention to provide an operation support system which provides an operator with a hint of keeping two objects of energy safety supply and operation cost reduction in compatibility by presenting a target operation pattern of an energy supply facility for each energy form to the operator according to the demand continuously fluctuating on some variable factors in a plurality of energy supply devices for supplying different energy forms such as a cogeneration energy supply device and in an energy supply system provided with a plurality of energy demands.
It is another object of the present invention to provide an operation support system which provides an operator with a hint on the operating method of keeping the energy safety supply and the operation cost reduction in compatibility in an energy supply facility for supplying energy in response to electric power and head demands fluctuating on variable factors.
According to a first aspect of the solving means provided by the invention, an energy supply facility for supplying different energy forms is arranged to predict an upper and a lower limits of a demand of each energy form and present an operator with a target operation pattern of each device for each energy form with the upper and the lower limits, the target operation pattern being based on the upper and the lower limit values of the demand. For deriving the upper and the lower limits of the target operation pattern, such upper and lower limits of the target operation pattern as reducing the operation cost as much as possible are derived in consideration of the error range of the energy demand prediction caused by variable factors. The present invention may present the operator with the upper and the lower limits of the target operation pattern. Hence, the operator can concretely obtain the operating policy of supplying energy with safety and reducing an operation cost.
In particular, the present invention presents an operation with not the target operation pattern but the upper and the lower limit of the target operation pattern of each energy form. The operator thus clearly gets to know the reliability of the target operation pattern. For example, if the width between the upper and the lower limits of a certain target operation pattern is narrow, the target operation pattern is difficult to suffer from the adverse effect of the demand prediction error. It means that the target operation pattern has a high reliability. Conversely, if the width between the upper and the lower limits of a certain target operation pattern is wide, the target operation pattern is easy to suffer from the adverse effect of the demand prediction error. It means that the target operation pattern has a low reliability.
As mentioned above, the application of the present invention makes it possible for the operator to get to know all the operation policies including all the factors up to the reliability of the target operation pattern. The reliability of the target operation pattern, termed herein, indicates how much the operator may follow the target operation pattern with fidelity. It means that if the reliability is lower, the operator is not required to follow the target operation pattern so much, while if it is high, the operator should follow the target pattern with fidelity.
According to the second aspect of the solving means provided by the present invention, the operation support system is arranged to present an operator with a target operation pattern probability density distribution. Like the first aspect, the operator can concretely obtain a hint on the operating method in keeping the energy safety supply and the operation cost reduction in compatibility. For example, if the peak of the density distribution is low and the skirts thereof are wide, it means that the width between the upper and the lower limits of the target operation pattern is wide in the first method. Conversely, if the peak of the target operation pattern probability density distribution is high and the skirts thereof are narrow, it means that the width between the upper and the lower limits of the target operation pattern is narrow in the first method.
According to the present invention, by presenting the upper and the lower limits of the target operation pattern derived in consideration of the demands fluctuating on variable factors to the operator of the energy facility, the operator is given an effective support in keeping the energy safety supply and the operation cost reduction in compatibility.
Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.